GH-352: Add Tunnel CLI option "edge-bind-address" (#870)

* Add Tunnel CLI option "edge-bind-address"

edgediscovery/allregions/discovery.go

@@ -41,6 +41,19 @@ const (
 	IPv6Only ConfigIPVersion = 6
 )
 
+func (c ConfigIPVersion) String() string {
+	switch c {
+	case Auto:
+		return "auto"
+	case IPv4Only:
+		return "4"
+	case IPv6Only:
+		return "6"
+	default:
+		return ""
+	}
+}
+
 // IPVersion is the IP version of an EdgeAddr
 type EdgeIPVersion int8
 

edgediscovery/dial.go

@@ -15,12 +15,16 @@ func DialEdge(
 	timeout time.Duration,
 	tlsConfig *tls.Config,
 	edgeTCPAddr *net.TCPAddr,
+	localIP net.IP,
 ) (net.Conn, error) {
 	// Inherit from parent context so we can cancel (Ctrl-C) while dialing
 	dialCtx, dialCancel := context.WithTimeout(ctx, timeout)
 	defer dialCancel()
 
 	dialer := net.Dialer{}
+	if localIP != nil {
+		dialer.LocalAddr = &net.TCPAddr{IP: localIP, Port: 0}
+	}
 	edgeConn, err := dialer.DialContext(dialCtx, "tcp", edgeTCPAddr.String())
 	if err != nil {
 		return nil, newDialError(err, "DialContext error")